Hello, Yes. As you suspected, inverted nipple is one of the sign of breast cancer if it occur all of sudden in few days to months. But it can occur also occur commonly in old age due to loss of elastic tissues and fatty tissues in breast. This need further evaluation like physical examination to rule out any hard lump and lymph nodes in axilla. If the physical findings suggestive of malignancy like hard lump, enlarged lymphnodes, discharge from nipple etc ,then you need further investigations like Mammogram, Ultrasound breast and CT scan if necessary. However if the mass is found and it is too confirmed as cancer by biopsy studies, then you might need surgery or chemotherapy or combination of both depending on the type of cancer. Hope this helps. Please write back for further queries. Wishing you good health.